Pneumatic tires may be considered or constructed of two major parts. The main portion or carcass includes beads adjacent the area where it is mounted upon the wheel. The carcass also has sidewalls extending from the beads to a crown portion. The second major portion of a tire is the tread mounted on the crown and made of a less abrasion resistant rubber. During normal use, the tread will become worn more quickly than the carcass whereafter the carcass can be retreaded with new tread portion. Alternately, the entire tire can be discarded or recycled for the generation of a new tire or other rubber product.
The concept of replacing worn treads without vulcanization offers many advantages. The most significant advantage is the time and cost savings. Since the life of the carcass is several times longer than the life of the tread, replaceable treads can extend the life and utility of a normal tire. They also permit the changing of tread design for a particular usage of the vehicle upon which the tire is mounted. Replaceable treads are also advantageous in that the tread can be replaced upon a carcass without the carcass being removed from the vehicle upon which it is mounted. This has a particular benefit in applications such as off the road uses. More specific benefits are found in the aircraft industry wherein plural tires are mounted on a common axle. In such situations, an inboard tire tread can be replaced without removing the exterior tire from the axle. This is done by merely deflating both tires and replacing the new tread on the inboard tire first.
There have been many approaches to removable tread tires in the past. Some approaches are described in U.S. Pat. Nos. 2,874,742; 3,750,733; and 4,050,495. These patents illustrate a long-standing appreciation for the need of a removable tread tire. The fact that removable tread tires have not met with commercial success illustrates deficiencies in the prior art approaches.